DENTAL CARIES IN RELATION TO MATURITY

Transcription

1 THE PREVALENCE OF DENTAL CARIES IN RELATION TO MATURITY BY J. N. MANSBRIDGE From the Department ofpublic Health and Social Medicine, University of Edinburgh (RECEIVED FOR PUBLICATION MARCH 27, 1958) This study constitutes part of an investigation of the epidemiology of dental caries in 4,034 Edinburgh children in the age range 5-17 years. Of this total sample, 1,730 children were examined as part of a joint investigation with H. S. Provis and R. W. B. Ellis, who were making an anthropometric study of the children (Provis and Ellis, 1955). Therefore for this group of children data relating to certain anthropometric measurements were available in addition to the dental findings. As socio-economic factors often influence growth, it was decided that a proportion of this sample of children should derive from private, fee-paying schools. Because of the influence of these factors on growth, it seemed not unreasonable to suppose that they could also influence dental health. When the dental state of children from fee-paying schools was compared with that of an otherwise comparable group of children from non-fee-paying schools differences in dental caries experience were found to exist. Thus, in the deciduous dentition, prevalence of dental caries was found to be lower among the fee-paying than amongst the non-fee-paying group, while in the permanent dentition the reverse was observed; that is, dental caries was now found to be more prevalent among the fee-paying than among the non-fee-paying children. Furthermore, it was also found that the proportions of the various tooth surfaces attacked by caries differed between these two classes of children. This division of the sample distinguished unmistakably two distinct groups of differing social environments. The information available relating to the occupation of the child's father was in most instances insufficiently precise to discriminate between the various social levels of which the nonfee-paying children were comprised. For this reason these children constituted a socially heterogeneous group. It is well recognized that differences in both stature and weight of children vary according to socioeconomic level and, since such variation is probably related to standards of diet and nutrition, the possibility existed that physical differences within the non-fee-paying group of children might discriminate between the various social strata of which the group was composed, in terms of diet and nutrition. Clements (1953) examined data relating to heights and weights of British children over the past 70 years. These data show clearly the differences that exist in height and weight between children drawn from upper, middle and lower income groups, and also indicate that children are growing more quickly now than they were some years ago. Furthermore, while these changes have taken place in all social groups, the greatest increases have occurred in the lower income groups, with the result that the disparity between children from upper and lower income groups has now been greatly reduced. Of Analysis of the data suggested that independent considerable interest is the fact that during both aetiological factors operate in differing degree in the world wars this upward trend was interrupted, to two contrasting social groups and these findings, be continued again after World War I during the supported by evidence from the literature, suggest inter-war period. This effect of both world wars is the view that these effects reflect poorer structural interesting for Sognnaes (1948) showed that during quality of the teeth in the lower social class and a both wars there was a considerable reduction in the more caries-provoking diet of children from a higher prevalence of dental caries in those countries social class environment. involved. This reduction in caries was considered Thus, by selection, the children compared were to be related to dietary changes, particularly those in the main divided into those belonging predominantly to Social Class I, while the remainder that at the end of the wars after a delay of some years in regard to sugar consumption. He also showed (the non-fee-paying children) represented Social the prevalence of dental caries began to increase and Classes III, IV and V (Registrar General, 1931). continued towards the pre-war level. 455

2 456 ARCHIVES OF DISEASE IN CHILDHOOD Since, for this sample of Edinburgh school children, there were available data relating to lying height, nude weight and a clinical assessment of sexual maturity, it was decided that a comparison of dental caries experience with certain physical measurements of non-fee-paying children should be undertaken in order to see whether the differences in dental caries found between fee-paying and non-fee-paying children would be repeated between children of differing physique. The literature revealed only two investigations in which the relationship between physique and dental caries was studied. Cunningham (1934), in an investigation of the relation of dental caries to disease, menstrual experience and physical measurements in 11,117 young women aged 15 to 19 years, found some evidence that the tall women showed a higher prevalence of dental caries than those of medium or short stature. This difference was found to be statistically significant. Discussing these findings, she expresses the view that many of the women of years may not yet have attained full stature, and since dental caries increases with age, it was possible that the taller women were also among the oldest in the sample. It is unfortunate that no attempt was made to study the age distribution of these women. Hurme (1936), in a study of 54 case histories of first-year students, in which prevalence of caries, height and health records were compared, found that when the number of D.M.F. teeth (decayed, missing and filled) was compared with height, the relationship, although not well marked, showed the number of D.M.F. teeth to be slightly less in the shorter half of the group. However, when the extremes of the distribution were compared, the short individuals had fewer D.M.F. teeth than the tall. Furthermore, since most of the tall individuals happened to belong to the youngest age group, the difference between the tall and the short was obviously not a function of chronological age in this instance. The discrepancy between chronological and developmental age in individual children can be considerable and in consequence differences can exist between the number of teeth erupted at any given age. Therefore differences in total dental caries experience in children at the same age may be due in part to this. Also, even when all teeth have erupted, some individuals will have had their teeth exposed in the mouth to risk of attack for a longer period than others of the same chronological age. Boas (1933) presented data to show that in a homogeneous social group, development of the dentition and general physical development as measured by height are associated. Talmers (1952) also observed that children of both sexes who had erupted their second molars early, were usually advanced in both height and weight for their age. Conversely, those children who were late in eruption of the second molars were below average in height and weight. It was also noticed that the relationship between body size and eruption was more marked among the boys than among the girls. Clearly, then, any association found between prevalence of dental caries and physique might also be explained by differences in the rate of development, rather than by absolute differences in physique. Methods The Sample. This has been described previously (Provis and Ellis, 1955). Measurement of Dental Caries. The children were examined in the schools during school hours. The dental examinations were conducted using plane mouth mirrors and Ash No. 54 probes, and illumination was obtained by the use throughout of a portable lamp, using a 60-watt bulb. The dental findings were dictated to an assistant who recorded them on a standard dental chart. The D.M.F. index (Klein, Palmer and Knutson, 1938) has been used to measure the prevalence of dental caries of the permanent teeth in these children. Using this index, the dental caries experience of an individual is expressed in the sum of all decayed, missing and filled permanent teeth, thus past experience of the disease in terms of treatment, i.e. extractions and fillings, is included with present untreated carious teeth to give the total caries experience of the individual at the time of examination. Analysis. As a preliminary step in order to see whether or not any relationship existed between the incidence of dental caries and height and weight, the children were ranked in order of the greatest to least height and similarly for weight, for each age and for both sexes separately. Each yearly age group was then divided into thirds and comparison of dental caries experience was made between the greatest third and the least third for height and weight separately. Results. It was found that up to and including the age of 11 years in both sexes the differences in dental caries experience between the tallest and shortest and between the heaviest and the lightest were quite insignificant and inconsistent. However, from 12 to 17 years of age for both sexes the taller children showed a consistently greater number of D.M.F. teeth per child than those who were shorter at the same age, with one exception only; that was

3 THE PREVALENCE OF DENTAL CARIES IN RELATION TO MATURITY in girls aged 17 years, where the shortest girls showed an appreciably greater average number of D.M.F. teeth per girl than the tallest. When weight and dental caries experience were compared, the heaviest girls showed a consistently higher average number of D.M.F. teeth from 12 to 17 years than the lightest girls, but in boys the data showed less consistency and at 12, 13 and 17 years the lightest boys showed a higher average dental caries experience, but at 14, 15 and 16 showed the same trend as the girls, that is, the heaviest had the greatest D.M.F. Figures 1 and 2 illustrate the differences in D.M.F. between these two groups and the numerical data are presented in Appendix Tables 1 and 2. It was found that these differences could not be explained entirely on the basis of the numbers of teeth erupted, for the average number of D.M.F. teeth per 100 teeth erupted clearly indicated a higher incidence of caries in the taller and heavier children relative to the number of teeth erupted, compared with the shorter and lighter. Also, the differences in mean age of the children seemed inadequate to explain the differences shown in dental caries experience. As mentioned earlier, it was observed that under 12 years of age the differences in dental caries between the tallest and shortest and between the heaviest and lightest were both insignificant and IO. w 7 w 2 6 Average D.4F Perrmonent Teeth per Child 9 BOYS Tallest Shortest FIG. is I.-D.M.F. for inconsistent. This contrast and the age at which notable differences began to appear suggested the possibility that sexual maturation may exert some influence in the incidence of dental caries and be responsible for the differences in caries between groups of contrasting physiques. The data relating to dental caries prevalence in the total sample of Edinburgh children indicated that the greatest increase in the annual increment of caries was found to occur in girls between the ages of 13 and 14 years and in boys between 15 and 16 years of age, a difference of two years (Appendix Table 3). Provis and Ellis (1955), in a study of the same Edinburgh children, found that boys began to show evidence of sexual maturation on the average two years later than girls. The median age of pubescence in boys was years and in girls years, while the median age of adolescence was for boys years and for girls years. It is apparent that the peak increase in dental caries and the onset of adolescence correspond in time for both sexes. The suggestion is strong, therefore, that these two events may be related in some way. For these children a clinical assessment of sexual maturity, made by H. S. Provis, was available. Three grades of maturity were recognized, 'non- 10 Average DAM F Permanent Teeth per Child GIRLS AGE IN YEARS tallest and shortest third of age group. 457

4 458 ARCHIVES OF DISEASE IN CHILDHOOD pubescent', with no evidence of sexual development, 'adolescent' as an advanced stage of maturity, while the 'pubescent' grade was intermediate. The assessment of maturity in boys was determined by the Boys distribution of pubic and axillary hair, together with degree of development of the genitalia, according to the criteria of Ellis (1946). In girls, the beginning of pubescence was defined by breast enlargement, while the onset of menstruation was taken as the commencement of adolescence. Therefore for each yearly group in the upper and lower thirds for height and weight, the data relating to degree of maturation were examined. These data are presented in Table 1 as combined totals for all age groups and are also given in greater detail in Appendix Tables 4 and 5. It can be seen from these data that a very much larger proportion of the children in the upper thirds for both height and weight are in a more advanced stage of sexual maturation than those children who happen to be in the lower thirds. To determine whether an association existed between sexual maturation and the incidence of dental caries, a comparison of dental caries experience was made between children of the same age but at *different levels of maturation. For this purpose all the children for whom maturation data were available were taken as the sample. 10 Average D.M.F Permanent Teeth per Child 9 BOYS 8- Heaviest Lightest F ~~~~~~~~~~~~~~~ z v ~~~~~~~~~~~~~~~~~ l` w 7- w U- 61 TABLE 1 NUMBER OF CHILDREN IN THE DIFFERENT STAGES OF SEXUAL MATURATION Girls NP PB AD NP PB AD Tallest Shortest Heaviest Lightest NP Non-pubescent. PB =Pubescent. AD Adolescent. A preliminary examination of the data had revealed differences in dental caries between pubescent and adolescent children at the same age. However, differences were also observed in the number of teeth erupted in the different maturity groups even at the same age (Appendix Table 6). These differences were not large and it was clear that they contributed in part only to the differences in dental caries. For this reason it was decided that comparison between the different maturity grades would be confined to those children who had erupted all permanent second molars. In this way comparison would be made between children of the same age and sex and in approximately an equal stage of dental development to examine the relationship, if any, between sexual maturation and the incidence of dental caries. Averoge D M.F Permanent Teeth per Child GIRLS 13 4 AGE IN YEARS FIG. 2.-D.M.F. for heaviest and lightest third of age group.

5 THE PREVALENCE OF DENTAL CARIES IN RELATION TO MATURITY 459 When these requirements had been met, the are more mature at the same age. Furthermore, distribution of children by age in each of the three the adolescent children have an average number of maturity gradings was such that only two comparisons could usefully be made: for the total Edinburgh sample at their age, while D.M.F. teeth which more closely approximate that (1) Between 31 pubescent and 35 adolescent girls, aged 13 years, and (2) Between 28 pubescent and 28 adolescent boys, aged 15 years. The number of children in the non-pubescent group who had erupted all four second molars was, at any age, too small to justify comparison with a pubescent group of equivalent age. It is generally recognized that attack of the teeth by dental caries is in part a function of the length of time that they are exposed in the mouth after eruption (Palmer, Klein and Kramer, 1938). Clements, Davies-Thomas and Pickett (1953) suggest that eruption of the second permanent molar and puberty are approximately coincident. It was considered possible, therefore, that differences in dental caries between children of the same age, who differed only in degree of maturation, might prove to be merely a reflection of the differences in time of eruption of the second molar. For example, it can be expected that the second molars of those children who are adolescent have been erupted in the mouth for a longer period than is the case of those children who are only pubescent at the same age. A second comparison was therefore made between the adolescent and pubescent children of both sexes in which the second molars were excluded from consideration. The results of these comparisons are presented in Tables 2, 3, 4 and 5. It can be seen that those children who are less advanced in maturity have a smaller number of decayed, missing and filled teeth than those who TABLE 2 MEAN NUMBER OF DECAYED, MISSING AND FILLED TEETH IN 13-YEAR-OLD GIRLS Mean Mean Maturity Grading No. No. Teeth D.M.F. Erupted Teeth Pubescent * Adolescent *28 5 *40 Ungraded Total Edinburgh Sample TABLE 3 MEAN NUMBER OF DECAYED, MISSING AND FILLED TEETH IN 15-YEAR-OLD BOYS Mean Mean Maturity Grading No. No. Teeth D.M.F. Erupted Teeth Pubescent Adolescent Ungraded Total Edinburgh Sample the pubescent children have an average more appropriate to a younger age. The influence of the second molar upon the average number of D.M.F. teeth is considerable, but even when these teeth are excluded, a difference between the two maturity groups remains, which is in the same direction as before. An examination of the distribution of dental caries of the individual teeth revealed no significant differences in distribution, that is, the pattern of attack in the two groups was substantially the same. The only difference observed was in amount of caries as indicated by the D.M.F. values in Tables 2 and 3. To test the possibility that differences in degree of dental caries might exist between the two maturity groups, the data were arranged to present dental caries measured in terms of affected tooth surfaces. The results indicated, however, that dental caries measured in this way shows differences between the groups equivalent to those observed when using the D.M.F. index. For these data then, the D.M.F. index provides a good measure of dental caries experience. Thus far the evidence clearly suggests that degree of sexual maturation is associated in some way with the dental caries experience of the child. It was appreciated, however, that the number of children between whom comparison was made was of necessity small and, taking into account the high variability of dental caries in individuals, it was manifestly desirable that some measure of this possible association be obtained and tested. The comparison of dental caries experience between children in the greatest and least thirds of height and weight had shown that the difference in dental caries TABLE 4 MEAN NUMBER OF DECAYED, MISSING AND FILLED TEETH, SECOND MOLARS EXCLUDED, 13-YEAR-OLD GIRLS Maturity Grading No. Mean D.M.F. Teeth Pubescent *42 Adolescent TABLE 5 MEAN NUMBER OF DECAYED, MISSING *AND FILLED TEETH. SECOND MOLARS EXCLUDED, 15-YEAR-OLD BOYS Maturity Grading No. Mean D.M.F. Teeth Pubescent Adolescent

6 460 in these children might also have been influenced to some extent by differences in both the number of teeth erupted and chronological age. The interrelationship of these possible factors presented a complicated situation and therefore, in an attempt to disentangle the effects of these various factors, multiple regression equations were calculated separately for boys and girls, in which the number of D.M.F. teeth was used as the dependent variate and some or all of the following in differing combinations were taken as independent variates: Height Weight Age Number of teeth erupted ARCHIVES OF DISEASE IN CHILDHOOD Maturity with stages: Non-pubescent Pubescent Adolescent For this purpose, within the age range years the entire sample for which these data were available was used and consisted of 629 boys and 581 girls. As might be expected, the number of D.M.F. teeth increased with age and with the total teeth erupted, these two indices being, of course, themselves highly correlated. When the effect of these was discounted, a marked difference appeared between the sexes. Among boys there was a highly significant increase of D.M.F. teeth with maturity, but there was no such effect with girls. To investigate this further, the regressions were done in another way. In each year of age D.M.F. teeth were used as a dependent variate and the first and second stages of maturation (pubescent and adolescent) as independent variates. From the sums of squares and cross-products of these a pooled regression was done for boys and another for girls. The effect of this is to give a measure of the difference, over the range of ages studied, in number of D.M.F. teeth between children of like age according to which stage of maturation they had reached. These regressions for both sexes showed that the number of teeth erupted was significantly associated with the stage of pubescence, but not with adolescence. Discussion It has been shown that differences in dental caries exist between those children who are tallest and heaviest and those who are shortest and lightest in the same yearly age group. However, these differences in physique could not be ascribed only to differences in standards of nutrition, if at all, and in consequence the original objective of this comparison, which was to discover whether differences in physique might discriminate between differing social levels, has not been achieved. It can be seen from the data presented in Appendix Tables 1 and 2 that the tallest and heaviest children were on average fractionally older and had a greater number of teeth erupted. In addition, it was found that the great majority of the tallest and heaviest children had reached a more advanced stage of maturity than those who were shortest and lightest. With regard to the differences in dental caries between these children, it was appreciated that these differences could be due either to the greater number of teeth erupted, or to the slightly greater age of the tallest and heaviest children, or to both of these factors. However, neither of these seemed adequate to explain fully the observed differences in dental caries, although it was recognized that they could contribute in part. There remained, therefore, the generally more advanced maturity of the taller and heavier children as a possible factor in their greater prevalence of dental caries. It had also been observed that no consistent differences in caries experience existed between these two groups of children of contrasting physique up to 11 years of age, but that major differences were only found in the age group years, during the period from puberty to adolescence. Furthermore, the data relating to the incidence of dental caries in the larger total sample of Edinburgh children indicated that the greatest annual increment of caries corresponded in time with the onset of adolescence in both sexes. These facts therefore suggested that sexual maturation and susceptibility to caries may be associated in some way. A comparison between adolescent and pubescent children of the same chronological age, who had erupted all their second molars, revealed differences in dental caries for both sexes that seemed only attributable to differences in degree of sexual maturation, and further indicated that these differences involved the whole dentition, not only the more recently erupted second molars. However, Parfitt and Parfitt (1954), in a study of the caries experience of a number of individuals from childhood to middle age, as derived from the records of private practice, presented data which showed no change in the caries incidence rate between the ages of 6-21 years, and commented that, while it has been suggested that puberty may have some influence on caries incidence rate, the data examined by them in their study did not show any such change. Of the 60 cases studied in this age range, 20 showed no change in caries incidence rate, but the remaining 40 individuals showed variations in the caries rate during this period, as many showing a decrease as an increase. They concluded, therefore, that puberty did not affect the caries incidence rate measurably. The data provided by this study of Edinburgh children are insufficient to show what the mechanism involved in this phenomenon may be, but the find-

7 THE PREVALENCE OF DENTAL CARIES IN RELATION TO MATURITY 461 children of the same age could be explained in terms of differences in times of dental development, the possibility exists that these differences in caries ings, together with evidence from other studies, suggest a possible explanation. Boas (1933) presented data showing that in a homogeneous social group, development ofthe dentition and general physical development as measured by height are associated. He demonstrated that early dentition was related to early increase in stature. Talmers (1952) also observed that children of both sexes who had erupted their second molars early were usually advanced in both height and weight for their age. Conversely, she found that those children who were late in eruption of the second molars were below average in height and weight. Clements et al. (1953) found that there was a trend towards the earlier eruption of the lower C, PM, and M2 teeth in those children who showed physical signs of puberty compared with those who showed no signs of puberty. The data for Edinburgh children indicated that the tallest (and heaviest) children had a consistently greater number of teeth erupted than the smallest (and lightest) at approximately the same age, and are therefore in agreement with these other three studies. Also, the data given in Appendix Table 6, showing the average number of teeth found at various stages of physical maturation in both boys and girls, appear to confirm the view that tooth eruption and general physical development are closely related. Of particular interest are the findings of Ellis (1946) in a study of height and weight in relation to onset of puberty in boys aged years. He found that not only were boys of a higher maturity group heavier and taller than boys of the same age in a lower maturity group, but that difference between the growth curves could be demonstrated as far back as the sixth year. There is thus good evidence that general physical development and eruption of teeth are associated, and further, that those children who mature early have been early in general physical development from a much earlier age, while those in whom the onset of puberty is late, have been late in general physical development throughout their early years. It seems possible to suggest, therefore, that in terms of dental development, those who mature late (e.g. in this study, boys who at 15 are classed as pubescent) may have been late in eruption of their teeth throughout their whole period of dental development. In consequence their teeth would have been exposed to risk of attack by dental caries for a shorter period than in the case of those children who have erupted their teeth at the usual times or earlier. While the differences in decayed, missing and filled teeth between pubescent and adolescent experience may be dietary in origin. The period of sexual maturity is accompanied by a rapid acceleration in growth and in consequence nutritional needs are increased, together with corresponding increase in appetite. Widdowson (1947) presents data from which it is apparent that caloric intake reaches a peak for boys at 15 years of age and for girls at 14 years. Her data relating to total sugar consumption of children are also of some interest, showing that in boys, the highest average intake was 37 7 oz. per week at 15 years of age, and in girls 26 *0 oz. per week at the age of 14 years. Total sugar consumption included sugar taken as such, sweets including chocolate, jams, cakes, biscuits, sugar in puddings and in cooked fruit. It was also found that up to the age of 8, differences in sugar consumption between the sexes were negligible, but from 9 years upwards boys consumed more than girls and at 15 they were eating nearly twice as much. Between 15 and 18 years boys ate more than twice as much as girls of similar age. A finding of considerable importance was the very great variation in food consumption of children at the same age and the fact that these extreme variations were compatible with normal physical development. Ellis (1951), commenting upon this observation regarding variations in food consumption in individual children of the same age, poses the question as to whether maturity grading of children in such a study might not reveal less variation in caloric intake in relation to stage of maturity reached than was observed when the children were grouped by chronological age. Since an increased intake of refined carbohydrate, especially sugar in sticky form between meals, has been shown to be associated with an increase in susceptibility to dental caries (Gustafsson, Quensel, Lanke, Lundqvist, Grahnen, Bonow and Krasse, 1954), the high consumption of these items of diet by children in the years old age group suggests another possible explanation of the differences in dental caries found between pubescent and adolescent children of the same age. That is, those who mature physically early may then have subsisted for a longer period upon a diet containing a high level of refined carbohydrates than those of the same age who matured later. Gustafsson et al. (1954) clearly demonstrated the rapidity with which susceptibility to dental caries could be altered by increasing or decreasing the intake of sugars in certain forms, even in adults. These writers also pointed out that similar dietary changes in children might be expected to pro-

8 462 ARCHIVES OF DISEASE IN CHILDHOOD duce even more marked differences in susceptibility. Although two quite different possible explanations may be offered to account for the differences in dental caries experience found in this study between pubescent and adolescent children, these explanations are not mutually exclusive. It is therefore possible that both differences in time of development of the dentition and differences in susceptibility due to dietary changes may both play their part in producing the results described in this study. From the multiple regression analysis confirmation of previous findings in this study was obtained that, for boys, sexual maturity and dental caries incidence are associated and, more precisely, that this association is related to adolescence but not to pubescence. Furthermore, the differences in D.M.F. teeth between adolescent and pubescent boys of the same chronological age attributable to maturity alone was I 8 teeth. For girls, however, the differences in dental caries experience between those who are adolescent and those who are pubescent at the same age were not found to be significantly associated with stage of maturity. It is of some interest that Talmers (1952) noted that the relationship between body size and eruption of second molars was less marked in girls than in boys. This difference between the sexes was not expected since the previous evidence suggested that, if in fact sexual maturity and dental caries incidence were associated, it would have been so for both sexes inasmuch as: (1) For the total Edinburgh sample the greatest increment of dental caries was found to correspond in time with the onset of adolescence in both sexes, i.e., between 13 and 14 years in girls and 15 and 16 in boys. It was seen, however, that the increase in D.M.F. teeth in boys between 15 and 16 was greater than the increase in girls between 13 and 14 years. (2) The tallest and heaviest thirds of each yearly age group showed a significantly greater proportion of children in more advanced stages of maturity than those in the least thirds. This was true for both sexes. (3) The comparison between pubescent and adolescent children of the same chronological age, who had also erupted all their second permanent molars indicated that there was a higher incidence of caries in the adolescent children of both sexes and that this difference in caries affected the dentition as a whole, not only the second molars. It is recognized that individual variations in dental caries incidence are considerable and result in large standard deviations. Consequently because of this variability any difference in D.M.F. rates between groups of individuals must be large to be statistically significant. Taking all the evidence into account, the possibility exists that the difference in dental caries experience observed between girls at different stages of maturation may, in fact, be associated with maturity in much the same way as boys, even if not of such magnitude as to show a statistically significant relationship. It is concluded, therefore, from the evidence obtained that adolescence in boys is associated with a higher dental caries incidence than is found in pubescent boys of the same age. It is suggested that this may be due either to a longer total exposure of the teeth in the mouth or to dietary factors associated with adolescence, or to a combination of both factors together. Finally, the regressions for both sexes provided statistical evidence that the number of teeth erupted was associated with pubescence. This confirms the observations made from the data presented in Appendix Table 6, and also those of Clements et al. (1953). Summary and Conclusions Data are presented which show a relationship between dental caries experience and stage of sexual maturation in children. When children of the same chronological age and at an equal stage of dental development were compared, it was found that children further advanced in maturation showed a higher dental caries experience than those who were less advanced. Also this difference in dental caries appeared to influence the dentition as a whole. Possible reasons for this are discussed. From the evidence obtained in this investigation it is concluded that earlier sexual maturation is associated with an increased prevalence of dental caries in boys. For girls no statistically significant evidence was obtained to indicate that a similar relationship exists, although other evidence suggests that this may be so. Finally, it was also found that for both sexes those children who reach the stage of pubescence early have a greater number of permanent teeth erupted than non-pubescent children of the same chronological age. I wish to thank Professor J. H. F. Brotherston and Professor R. W. B. Ellis for their most helpful advice and criticism. I am also indebted to Dr. H. S. Provis for his co-operation in this study, to Dr. W. N. Boog Watson, Chief School Medical Officer and Mr. G. Moody, Chief Dental Officer, of the City of Edinburgh, for their most helpful co-operation in the collection of the original data. My sincere thanks are due to Dr. Barnet Woolf for his valuable statistical advice and to Miss M. Brown for her assistance in the computation of the raw data. REFERENCES Boas, F (1933). Hum. Biol., 5, 429. Clements, E. M. B. (1953). Brit. med. J., 2, , Davies-Thomas, E. and Pickett, K. G. (1953). Ibid., 1, 1421.

9 THE PREVALENCE OF DENTAL CARIES IN RELATION TO MATURITY 463 Cunningham, R. L. (1934). J. dent. Res., 14, 439. Ellis, R. W. B. (1946). Arch. Dis. Childh., 21, (1951). Brit. J. Nutr., 5, 151. CGustafsson, B. E., Quensel, C. E., Lanke, L. S., Lundqvist, C., Grahn6n, H., Bonow, B. E. and Krasse, B. (1954). Acta odont. scand., 11, 232. Hurme, V. 0. (1936). J. dent. Res., 15, 395. Klein, H., Palmer, C. E. and Knutson, J. W. (1938). (Wash.), 53, 751. Tallest Third Publ. Hlth. Rep. Palmer, C. E., Klein, H. and Kramer, M. (1938). Growth, 2, 149. Parfitt, G. J. and Parfitt, J. B. (1954). Brit. dent. J., 96, 183. Provis, H. S. and Ellis, R. W. B. (1955). Arch. Dis. Childh., 30, 328. Registrar General(1931). ClassificationofOccupations. H.M.S.O., London. Sognnaes, R. F. (1948). Amer. J. Dis. Child., 75, 792. Talmers, D. A. (1952). N.Y. St. dent. J., 18, 314. Widdowson, E. M. (1947). No APPENDIX TABLE 1 DENTAL CARIES IN RELATION TO HEIGHT Spec. Rep. Ser. Med. Res. Coun. (Lond.), Shortest Third Mean No. D.M.F Mean No. D.M.F. Mean Mean No. D.M.F. per 100 Mean Mean No. D.M.F. per 100 No. Age Teeth Teeth Teeth Age Teeth Teeth Teeth (yr.) Erupted per Child Erupted (yr.) Erupted per Child Erupted Boys Girls TABLE 2 DENTAL CARIES IN RELATION TO WEIGHT Heaviest Third Lightest Third Mean No. D.M.F. Mean No. D.M.F. Mean Mean No. D.M.F. per 100 Mean Mean No. D.M.F. per 100 No. Age Teeth Teeth Teeth Age Teeth Teeth Teeth (yr.) Erupted per Child Erupted (yr.) Erupted per Child Erupted Boys Girls TABLE 3 DENTAL CARIES PREVALENCE BY AGE AND SEX IN A SAMPLE OF 4,034 EDINBURGH CHILDREN Boys Annual Increment Annual Increment Age (yr.) No. Mean D.M.F. in Mean D.M.F. No. Mean D.M.F. in Mean D.M.F. Teeth per Child Teeth Teeth per Child Teeth * * *97 1* *63 0* Girls

10 464 ARCHIVES OF DISEASE IN CHILDHOOD TABLE 4 THE NUMBER AND PERCENTAGE OF BOYS IN THE VARIOUS STAGES OF SEXUAL MATURATION Number Percentage - l~~~ NP PB AD NP PB AD NP PB AD NP PB AD 1- Tallest Shortest Tallest Shortest Age Group Total Tota Heaviest _ _ 10 Lightest _ _ II Heaviest Lightest 100 _ Total NP = Non-pubescent. PB = Pubescent. AD = Adolescent. TABLE 5 THE NUMBER AND PERCENTAGE OF GIRLS IN THE VARIOUS STAGES OF SEXUAL MATURATION Number Percen age Age Group NP PB AD NP PB AD NP PB AD NP PB AD Tallest Shortest Tallest Shortest _ Total Heaviest Lightest Heaviest Lightest _ _ Total NP = Non-pubescent. PB =Pubescent. AD =Adolescent. TABLE 6 MEAN NUMBER OF TEETH ERUPTED PER CHILD AND ASSESSMENT OF SEXUAL MATURATION Boys Girls Age (yr.) Assessment of Sexual Maturity No. Mean No. of Teeth Erupted No. Mean No. of Teeth Erupted 11 Non-pubescent Pubescent * Non-pubescent 70 24* *69 Pubescent.21 25* Adolescent Non-pubescent Pubescent Adolescent Non-pubescent Pubescent Adolescent * Pubescent Adolescent ~ ~ ~ ~~~l-